Old story

Lo scandalo della principessa ormai è una vecchia storia, trita e ritrita, ma i giornali ci vanno ancora a nozze

The princess' scandal is old news, but the press keeps having a field day with it

You have told that story at least ten times; it's old hat

Hai raccontato quella storia almeno dieci volte; è una storia trita e ritrita

The expression dates from the late 19th century, and it probably refers to the fact that hats go out of fashion before they actually wear out